let id = 10
let name = 'jack杰克'
let age = 18
let s1 = JSON.stringify({id,name,age})
console.log(s1)

let obj = JSON.parse(s1);
console.log(obj.id)
console.log(obj.name)

let user = {
    "username":"李强",
    "userage":22
}

let {username,userage} = user;
console.log(username)
console.log(userage)
